Exhaust diagram

Every car exhaust is made up of a number of vital components. Some of the key parts and the role they play are listed below.

Exhaust Manifold
The exhaust manifold conducts gases from the combustion chambers of the engine to the exhaust pipe. It is usually constructed of cast iron and smooth curves to improve the flow of exhaust.

Catalytic Converter
As already mentioned, the catalytic converter reduces harmful emissions from engine exhaust. It uses a combination of heat and metals that act as catalysts. A catalyst is a metal (or chemical) that causes other chemicals to go through a reaction without being affected itself. The inside of the catalytic converter consists of metals like aluminum oxide, platinum palladium. These metals cause the carbon monoxide and hydrocarbons to react and produce water vapor and carbon dioxide which are much less harmful to the atmosphere.

The muffler alone cannot always quiet all of the engine noise. Many car exhaust systems also include a resonator which is like a mini muffler. They are usually straight pipes filled with sound muffling materials. The resonator can be either before of after the muffler in the exhaust system.

Car Exhaust diagram.

Exhaust Pipe
Exhaust pipe connects all the other parts of the exhaust system.

The muffler quiets the noise of the engine. There are two kinds of mufflers. Once uses baffled chambers to reduce noise. As sound waves move through this type of muffler, they bounce off the baffles and expend their energy inside the muffler, losing force and volume. The other type forces the exhaust straight through a perforated pipe that contains metal, fiberglass, or some other kind of sound-absorbing material. This muffler is designed to reduce back pressure (exhaust going back up the pipes) and consequently makes a little more noise.

Tail Pipe
The tail pipe comes out of the muffler, past the rear bumper of the vehicle, directing exhaust gases away from the vehicle. On many newer cars it also serves as a decorative function and is tipped in chrome.

Exhaust system-Mufflers

It's amazing what a difference a muffler can make to reducing the noise levels of an exhaust system. Exhaust gases leave the engine under extremely high pressure. If these gases escaped directly from the engine the noise would be tremendous. For this reason, the exhaust manifold sends the gases to a muffler where they go through metal plates, or tubes, with a series of holes. The pressure of the gases is reduced when they pass through the muffler, so they go out of the tail pipe quietly.

A Diagram showing where the muffler is located on a car. (Click to enlarge)

There are two main types of muffler design. One type uses several baffled chambers to reduce noise. The other type sends the gases straight through perforated pipe wrapped in metal or fiberglass. This type of muffler is designed for the purpose of reducing back pressure and, consequently, makes slightly more noise. Some exhaust systems also have a resonator. They are added at the end of the exhaust system to take care of any noise that has made it through the muffler.

Mufflers can make a huge difference to the noise levels of an exhaust.

While the goal is to absorb energy that would otherwise be released as sound into the environment, mufflers do force engines to work somewhat harder pushing exhaust gas through them. Therefore, it is a common engine tuning practice to replace stock mufflers with versions that require less energy to force the gas through (usually described as lowering the "back pressure"). Such accessory mufflers can often increase a vehicle's power, but usually at the cost of less effective noise suppression.